Variable-voltage transformer.



No. 890,638. r PATENTED JUNE 16, 1908 a. F. GEHRKBNS.

VARIABLE VOLTAGE TRANSFORMER.

APPLIUATIOH rum) JULY 26, 1906. Rum/BB JAH. 91,1908.

Wit/7665 5;

- i 2 Edward r? Gab/"hens Amy - UNITED STATES PATENT OFFICE.

EDWARD F. GEHRKENS, OE SGHENEOTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION Q1" NEW YORK.

, i VARIABLE-VOLTAGE TRANSFORMER.

Specification of Letters ?c.t'ent.

Patented June is, 1908.

Application filed July 26, 1906, Serial No. 327,915. Renewed January 31, 1908. Serial No. 413,614.

To all 107mm it may concern:

Be it known that I, EDWARD 1*. Guns.-

KENS, a citizen of the United States, residing Y at Schenectady, county of Schenectady; State of New York, have invented certain: new and useful Improvements in Variable Voltage Transformers, of which the following member.

are indicated by B and C, respectively. This .the elllcieccy of such transformers, cl'nd r is a specification.

My invention relates to. variable-voltage transformers of a type proposed heretofore,

comprising a magnetic core with primary and secondary coils thereon, with. two movable magnetic members,-one arranged 130* open the magnetic circuit threading both thej primary and secondary coils, and the other to close a magnetic circuit outside of" the secondary coil. As these transformers have been designed heretofore, it has been nece sary leave,a space between the primary and secondary coils for the shunting magnetic member when it is moved into position. This spacing apart of the primary and secondary coils not only makes the structure of the transformer less com act, but produces considerable magnetic ealiage, so that even when the magnetic members are in the position of maximum induced voltage not ali'the primary flux threads the secondary coil. Consequently, the efficiency of the trans-- former is impaired, and the resctsnoeof the primary circuit is increased by this leakage flux. I

The object of my invention is to improve T accom lish this result by so arranging the secon ary coil and the movable magnetic .members that the primary and secondary bers joined ct both on s with primary and secondary coils sidc-by-side on the ceptral The primary and. secondary coils coil awe. Y from the urimar and With the two coils in the;..

1) serves wactically to close the magnetic;

circuit of the coi'e'A, softhat the transformer operates like on ordinary shell type transformer. "This position of the iecondarcoil is the position of maximum in uced v0 tage. To reduce the secondary voltage, the coil 0 is lowered out of line with the primary coil, carrying with it the member 1). A second member E is placed above the coil and, when the coil is lowered, this member is brought into the space vecated by the member l) and thecoil so as to close the magnetic circuit of the primary coil outside of the coil U. The mom er ll enters the core A before member Dleaves it, thereby gradually shuntthe primary flux around the secondary coil,

Any suitable means for moving the coil C and members. l) and E may be employed. I have indicated for this purpose a rope F passing over a pulley G and provided with a suitable counter-weight H.

Any other suitable operating means may be employed. Accordingly, I do 'not desire to limit myself to the particular construction and arrangement of parts here shown, but sim in the appended claims to cover all modifications which are within the scope of my invention:

What I claim as new, and desire to secure by Letters Patent of the United-States, is,

1. To a variablevoltcge transformer, a. magnetic'corc, flat primary and secondary coils sidc-by-sidc on said core, said secondary coil and the portion of. the core inclosed thereby being movable in the olane of the a magnetic member arranged. to be moved into the space vacated by said core portion.

2. e varieble-voltage transformer, a magnetic corc flat orimary and secondary coils side-by-sidc on said core, said secondary coil and the portion of the core inclosed thereby being movable in the lane ofthe coil away from the primary, in a magnetic member carried by the secondary coil adapted to be brought by the movement of the coil into the space vacated by said core portion.

3. In a variable-voltage transformer, an ())6I1 magnetic core, a flat primary coil thereon, a fiat secondary coil adjacent to the primary and movable in its own plane into and out of linewi'th' the primary coil, a magnetic mcmbcricarried within the secondary coil and adapted to complete the magnetic circuit of the primary coil when the secondary is in line therewith, and a second magnetic member carried outside the secondary coil and adaited to complete the magnetic circuit of the primary coil when the secondary is out of line therewith.

4. In a variablevoltage transformer, a

- magnetic core, flatprimary and secondary coils thereon, said secondary coil and the portion the core inclosed thereby being movable away from the primary in the plane of the secondary coil, and a magnetic member secured to and movable with the sec ondary coil adapted to complete a magnetic circuit for the primary coil outside of the secondary coil.

5. In a variable-voltage transformer, a

, magnetic core, flat primary and secondary coils thereon, the secondary coil and the portion of the core inclosed thereby being lmovable in the plane of the coil away from the primary, and a magnetic member arranged to e moved into position to close a magnetic circuit for the prlmarycoll out side of the'secondary coil.

'6. In a variable-voltage shell-type trans:

former, a magnetic core substantially recpartially surrounded by the remainder of the core, and a fiat secondary coil movable inits own plane in thahol-low center and inclosing a'mag'netic member movable with it, and a second magnetic member for completing the magnetic circuit of the primary coil when the secondary coil is moved out of inductive relation therewith.

' 7. In a variable-voltage 'shcll type transformer, a magnetic core substantially rectangular with a substantial] rectangular hollow center and a portion 0" the core pro jecting into this center, a, flat primary coil surrounding the projecting portion of the core and surrounded as to its external faces and sides by the remainder of the core, and a fiat secondary coil movable 'in its own plane within the hollow cepter and inclosing a magnetic member movable with it and adapted to be moved into line with the primary coil and com lete the magnetic circuit of theprimary coil: and a second magnetic member arranged to move with the secondary coil adaptedto complete the magnetic circuit of the primary coil outside of the secondary coil.

In witness whereof I have hereunto set my hand this 24th day of July, 1906.

EDWARD F. GEHRKENS. 

